Artesunate interacts with Vitamin D receptor to reverse mouse model of sepsis-induced immunosuppression via enhancing autophagy

Shenglan Shang; Jiaqi Wu; Xiaoli Li; Xin Liu; Pan Li; Chunli Zheng; Yonghua Wang; Songqing Liu; Jiang Zheng; Hong Zhou

NF-κB is a vital transcription factor, and the NF-κB signaling pathway links pathogenic signals and cellular danger signals, thus organizing cellular resistance to invading pathogens, which is a network hub responsible for complex biological signaling (Albensi & Mattson, 2000; Kaltschmidt & Kaltschmidt, 2009 ). NF-κB p65 was reported to physically interact with VDR in mouse embryonic fibroblast cells and intestinal cells (Sun et al., 2006; Wu et al., 2010) . Our previous studies have shown that AS could significantly inhibit LPS-induced . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.02.26.966143 doi: bioRxiv preprint TLR4/TRA6/NF-κB activation in macrophages, leading to reduced release of proinflammatory cytokines (Kuang et al., 2018; Li et al., 2008) , thereby playing an anti-inflammatory role. Herein, we focused on its function in sepsis immunosuppression stage, and discovered that NF-κB p65 was negatively regulated by VDR due to the physical interaction between them in macrophages. Importantly, AS prevented the interaction between VDR and NF-κB p65 in LPS-tolerance cells, leading to a marked increase in nuclear NF-κB p65 translocation and expressions of downstream target genes such as TNF-α and IL-6. Furthermore, we found that AS decreased the binding between VDR and the promoter region of ATG16L1, leading to a decline in nuclear translocation of VDR and decreasing the negative transcription of ATG16L1, and lastly AS enhanced autophagy activities through binding VDR. Furthermore, knocking down VDR expression reversed the autophagy related proteins levels in immunosuppression stage, and over expressing VDR resulting in a failure of AS-promoting the autophagy related proteins levels. Thus, we concluded that AS interacted with VDR to reverse immunosuppression stage was autophagy involved. Taken together, we think AS interacted with VDR thereby inhibited the nuclear translocation of VDR and also inhibited physical interaction between VDR and NF-κB p65 in LPS tolerance macrophages, then promoted nuclear translocation of NF-κB p65, enhancing autophagy and activating the transcription of NF-κB p65 target genes such as pro-inflammatory cytokines.